How does the law of conservation of energy apply to the burning of coal?

When the coal is in its normal state, there is a lot of energy in it called chemical/potential energy. This means that the energy is inside the bonds of coal. When coal is burned, the energy is released and converted into light and heat energy.

The law of conservation of energy states that on both sides of an equation, the amount of energy, in general, stays the same. Personally, I do not believe that it is 100% accurate since in nuclear fission, mass turns into energy, but in this case, it is true. Released from the coal is only as much energy as the coal orriginally had.